NAVIGATION APPARATUS

PURPOSE:To enable precise detection of a position at all times by executing calculation of-the position on the basis of the result of correction of a detected value of an advance azimuth angle by a modified value of an azimuth angle. CONSTITUTION:In an azimuth computation processing element 2, an advance azimuth angle thetac is computed on the basis of detection voltages Vx and Yx inputted from a geomagnetic sensor 1. Next, in an azimuth modification processing element 7, computation is executed on the basis of the azimuth angle thetac supplied from the processing element 2, a signal (f) supplied from a road collation processing element 6 and an azimuth angle thetar of a road, an angle difference thetas between the azimuth angles thetac and thetar is thereby determined and subtracted from the azimuth angle thetac and thereby a true azimuth angle theta is determined. In a distance computation processing element 4, a pulse outputted from a distance sensor 3 is counted and a running distance lfor each unit time is outputted. Then, in the processing element 6, the azimuth angle thetaand the distance l supplied from the processing elements 7 and 4 are processed by computation, the current calculated position of an automobile is collated with a road map read out of a storage circuit 5, the calculated position is thereby corrected and accurate position data are displayed as the current position of the automobile on a map screen.